Study finds human activity pushing tropics further poleward

Man-made pollution appears to be having a bigger effect on the planet than previously thought. Earlier studies had indicated the relationship shared between pollution and a shift in tropical and sub-tropical regions. It was believed that the expansion of the tropics could spread to between 222 and 553 km in the next 25 years. Now, new findings show that this shift is even more closely related to human activity. According to a study published in Nature, man-made tropospheric ozone and black carbon aerosols that are emitted mainly in the low- to mid-low latitudes of the Northern Hemisphere are pushing the tropics further poleward.

What this bodes for the planet and those living in the sub tropics is that if the tropics are indeed moving towards the poles, then the sub tropics could become drier than they are. This means less rainfall and in a world where lives are dictated by nature’s bounties, economies and societies could be adversely affected.

While the negative impact of humans is well known and documented, the study only further establishes the effect we have not just on our immediate surroundings but the planet as a whole. For instance, if the trend continues, then the southern parts of the United States could become drier and storm systems could shift further northward than they were three decades ago.

The drying of the sub tropics has meant an increasingly wet higher mid-latitude. Since regions have conformed to certain climatic conditions over the centuries and have based their economies and societies on these trends, such shifting of the tropics and changing weather patterns will not bode well.

Of course, we’ve also seen policies being implemented that seek to reduce black carbon soot on an international scale. If they can be enforced properly, then the trend could be reversed as the effects of black carbon are short-lived compared to other pollutants.